type
  RInitArgs = packed record
    iApplication: TApplication;
    iScreen: TScreen;

    oForm: TForm; // идея возвращать форму, не нашла продолжения
  end;

  RCloseArgs = packed record
    //урезал в рамках примера
  end;

  TInit = function(var aInitArgs: RInitArgs): Boolean; stdcall;
  TClose = function(var aCloseArgs: RCloseArgs): Boolean; stdcall;

var
  lFilePath: String;

  lHandle: THandle;
  lInit: TInit;
  lClose: TClose;

  lInitArgs: RInitArgs;
  lCloseArgs: RCloseArgs;

  lConnectError: String;
begin
// ...код загрузки dll, означивание lFilePath...
  try
      Application.Initialize;
      Application.MainFormOnTaskbar := True;

      lHandle := LoadLibrary(PChar(lFilePath));
      if lHandle = 0 then
        RaiseExceptionFormat(rsLoadLibraryError, [lFilePath, GetLastError]);

      lInit := GetProcAddress(lHandle, cEntryInit);
      if not assigned(lInit) then
        RaiseExceptionFormat(rsLibraryEntryNotFound, [lFilePath, cEntryInit]);

      lClose := GetProcAddress(lHandle, cEntryClose);
      if not assigned(lClose) then
        RaiseExceptionFormat(rsLibraryEntryNotFound, [lFilePath, cEntryClose]);

      lInitArgs.iApplication := Application;
      lInitArgs.iScreen := Screen;

      if not lInit(lInitArgs) then
        RaiseException(rsInitError);
      try
        Application.Run;
      finally
        lClose(lCloseArgs);
      end;
    except
      on E: Exception do
        begin
          ShowMessage(rsAppRunError);
        end;
    end;
end.

function Init(var aInitArgs: RInitArgs): Boolean; stdcall;
var
  lCloseArgs: RCloseArgs;
begin
  Result := False;
  try
    gApplication := Application;
    gScreen := Screen;

    Application := aInitArgs.iApplication;
    Screen := aInitArgs.iScreen;

    Application.ShowHint := True;
    Application.CreateForm(TMainForm, gForm);
    Application.CreateForm(TResourceForm, ResourceForm); // все ImageList-ы на TResourceForm
    aInitArgs.oForm := gForm;

    gForm.Initialize;

    Result := True;
  except
    on E: Exception do
      begin
        Result := False;

        Close(lCloseArgs);
      end;
  end;
end;

function Close(var aCloseArgs: RCloseArgs): Boolean; stdcall;
begin
   if gForm <> nil then
     begin
       gForm.Finalize();
       gForm.Free;
       gForm := nil;
     end;

  Application := gApplication;
  Screen := gScreen;
end;

exports
  Init,
  Close;

begin
end.

TMainForm = class(TForm)
  PageNavigatorFrameMain: TPageNavigatorFrame;
  procedure FormCreate(Sender: TObject);
  procedure FormDestroy(Sender: TObject);
private
public
  procedure Initialize();
  procedure Finalize();
end;